Terephthalic acid esters formation

ABSTRACT

The present disclosure relates to the formation of dimethyl terephthalate (DMT). The present invention also relates to the depolymerization of polyethylene terephthalate (PET) and the recovery of terephthalic acid and ethylene glycol.

CROSS-REFERENCE

This application is a continuation-in-part of U.S. patent application Ser. No. 17/837,801, filed Jun. 10, 2022, which is a continuation of U.S. patent application Ser. No. 17/024,159, filed Sep. 17, 2020, now issued as U.S. Pat. No. 11,401,398, issued on Aug. 2, 2022, which is a continuation of U.S. patent application Ser. No. 16/450,807, filed Jun. 24, 2019, now issued as U.S. Pat. No. 10,808,096, issued on Oct. 20, 2020, which claims the benefit of U.S. Provisional Application No. 62/689,597, filed Jun. 25, 2018, and this application is a continuation-in-part of U.S. patent application Ser. No. 17/350,979, filed Jun. 17, 2021, which is a continuation of U.S. patent application Ser. No. 17/004,764, filed Aug. 27, 2020, which is a continuation of U.S. patent application Ser. No. 16/259,980, filed Jan. 28, 2019, now issued as U.S. Pat. No. 10,793,508 issued on Oct. 6, 2020, which is a continuation of U.S. patent application Ser. No. 15/706,484, filed Sep. 15, 2017, now issued as U.S. Pat. No. 10,252,976, issued on Apr. 9, 2019, each of which is incorporated herein by reference in its entirety.

FIELD OF THE INVENTION

The present disclosure relates to the formation of ester derivatives from polyesters and more specifically to the formation of terephthalic acid esters from polyethylene terephthalate (PET) or poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG). The present disclosure also relates to the formation of dimethyl terephthalate (DMT).

BACKGROUND OF THE INVENTION

The polyethylene terephthalate (PET) bottle resin market has been growing strongly as PET resins have replaced glass in carbonated soft drink, bottled water and food containers.

Dimethyl terephthalate (DMT) is primarily used in the manufacture of polyethylene terephthalate (PET) for fiber, film, container plastics, and specialty plastics applications.

The largest polyester sector is the fibers market where it is used to make clothes, home textiles such as sheets and curtains, carpets and rugs, and industrial products such as tire cord, seat belts, hoses and ropes. PET film is utilized in electrical applications such as dielectric metal foil capacitors and for food packaging.

The growth in polyester has not been converted into DMT demand. For most grades of polyester used in textiles and food and beverage containers, it is more economical to use purified terephthalic acid rather than DMT.

SUMMARY OF THE INVENTION

Disclosed herein is a process for the transformation of a polyester selected from polyethylene terephthalate and poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) into a terephthalate of Formula (I):

-   -   wherein R¹ and R² are independently selected from hydrogen,         C₁-C₆ alkyl, C₁-C₆ haloalkyl, C₁-C₆ hydroxyalkyl, optionally         substituted C₃-C₈ cycloalkyl, optionally substituted (C₁-C₆         alkyl)(C₃-C₈ cycloalkyl), optionally substituted aryl, and         optionally substituted (C₁-C₆ alkyl)(aryl); provided that one of         R¹ or R² is not hydrogen;     -   the process comprising admixing the polyester with a mixture         comprising:         -   (a) a solvent for swelling the polyester;         -   (b) an alcoholic solvent; and         -   (c) a sub-stoichiometric amount of an alkoxide.

In some embodiments, R¹ or R² is methyl.

In some embodiments, the alcoholic solvent is selected from methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-1,4-diyldimethanol, phenol, benzyl alcohol, and any combinations thereof.

In some embodiments, the alcoholic solvent is methanol.

In some embodiments, the solvent for swelling the polyester is selected from a non polar solvent, a polar aprotic solvent, a polar protic solvent, and any combinations thereof.

In some embodiments, the solvent for swelling the polyester is selected from DMSO, DMF, acetone, a halogenated solvent, n-hexane, nitrobenzene, methanol, benzyl alcohol, benzaldehyde, and any combinations thereof.

In some embodiments, the solvent for swelling the polyester is a halogenated solvent.

In some embodiments, the ratio of solvent for swelling the polyester to alcoholic solvent is between about 0.1:1 and about 2:1 (w:w).

In some embodiments, the ratio of solvent for swelling the polyester to alcoholic solvent is between about 0.5:1 and about 1:1 (w:w).

In some embodiments, the alkoxide is selected from an alkali metal alkoxide, an alkaline earth metal alkoxide, a metal alkoxide, an ammonium alkoxide and any combinations thereof.

In some embodiments, the alkoxide is generated in-situ by addition of an alkali metal, an alkaline earth metal, or a metal to the alcoholic solvent.

In some embodiments, the ratio of polyester to alkoxide is between about 15:1 and about 125:1 (w:w).

In some embodiments, the ratio of polyester to alkoxide is between about 20:1 and about 25:1 (w:w).

In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed until an about 80% yield of the terephthalate of Formula (I) is achieved.

In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed without external heat.

In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed at atmospheric pressure.

Also disclosed herein is a process for the transformation of polyethylene terephthalate into dimethyl terephthalate, comprising admixing the polyethylene terephthalate with a mixture comprising:

-   -   (a) a solvent for swelling the polyethylene terephthalate;     -   (b) methanol; and     -   (c) a sub-stoichiometric amount of an alkoxide.

In some embodiments, the solvent for swelling the polyethylene terephthalate is selected from a halogenated solvent, DMSO, benzyl alcohol, methanol, and any combinations thereof.

In some embodiments, the ratio of polyethylene terephthalate to alkoxide is between about 20:1 and about 25:1 (w:w).

In some embodiments, the alkoxide is selected from sodium methoxide, potassium ethoxide, aluminium tri-n-propoxide, and tetrabutylammonium methoxide.

In some embodiments, the ratio of solvent for swelling the polyester to methanol is between about 0.5:1 and about 1:1 (w:w).

In some embodiments, the admixing of the polyethylene terephthalate with the solvent for swelling the polyethylene terephthalate, the alkoxide, and the methanol is performed until an about 80% yield of dimethyl terephthalate is achieved.

Also disclosed herein is a reaction mixture comprising:

-   -   (a) a polyester selected from polyethylene terephthalate and         poly(ethylene glycol-co-1,4-cyclohexanedimethanol         terephthalate);     -   (b) a solvent for swelling the polyester;     -   (c) an alcoholic solvent; and     -   (d) a sub-stoichiometric amount of an alkoxide.

In some embodiments, the alcoholic solvent is selected from methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-1,4-diyldimethanol, phenol, benzyl alcohol, and any combinations thereof.

In some embodiments, the solvent for swelling the polyester is selected from a non polar solvent, a polar aprotic solvent, a polar protic solvent, and any combinations thereof.

In some embodiments, the solvent for swelling the polyester is a halogenated solvent and the alcoholic solvent is methanol.

In some embodiments, the ratio of solvent for swelling the polyester to alcoholic solvent is between about 0.5:1 and about 1:1 (w:w).

In some embodiments, the ratio of polyester to alkoxide is between about 15:1 and about 30:1 (w:w).

In some embodiments, the alkoxide is selected from sodium methoxide, potassium ethoxide, aluminium tri-n-propoxide, and tetrabutylammonium methoxide.

In some embodiments, the alkoxide is sodium methoxide.

Disclosed herein is a process for the depolymerization of polyethylene terephthalate (PET) to form a terephthalate; the process comprising admixing polyethylene terephthalate (PET) with a mixture comprising a glycoxide.

In some embodiments of the process, the mixture further comprises a solvent.

In some embodiments of the process, the solvent is selected from methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-1,4-dimethanol, phenol, benzyl alcohol, and any combinations thereof. In some embodiments of the process, the solvent is methanol.

In some embodiments of the process, the solvent is added to the polyethylene terephthalate (PET) prior to the addition of the glycoxide.

In some embodiments of the process, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide for about 15 mins to about 120 mins. In some embodiments of the process, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide for about 60 min.

In some embodiments of the process, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide at a temperature between about 50° C. to about 100° C. In some embodiments of the process, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide at a temperature of about 60° C.

In some embodiments of the process, the terephthalate is dimethyl terephthalate (DMT).

In some embodiments of the process, the glycoxide is sodium glycoxide. In some embodiments of the process, the glycoxide is mono sodium glycoxide. In some embodiments of the process, sodium glycoxide is provided as a suspension.

In some embodiments of the process, the mono sodium glycoxide suspension is prepared by a process comprising:

-   -   a) heating mono ethylene glycol;     -   b) adding sodium hydroxide thereby forming mono sodium         glycoxide;     -   c) drying the mono sodium glycoxide;     -   d) suspending the dried mono sodium glycoxide into a suspending         solvent; and     -   e) aging the suspension.

In some embodiments of the process, step (a) is performed at a temperature between about 70° C. to about 100° C. In some embodiments of the process, step (a) is performed at a temperature of about 90° C.

In some embodiments of the process, the ratio of mono sodium glycoxide to the suspending solvent is between about 0.05:1 to about 0.5:1 (mol/mol).

In some embodiments of the process, the ratio of mono sodium glycoxide to the suspending solvent is about 0.2:1 (mol/mol).

In some embodiments of the process, the suspending solvent is methanol.

In some embodiments of the process, the suspension is aged for about 1-14 days. In some embodiments of the process, the suspension is aged for about 1-7 days. In some embodiments of the process, the suspension is aged for about 7 days.

In some embodiments of the process, the ratio of glycoxide to polyethylene terephthalate (PET) is between about 1:2 and about 1:20 (mol/mol).

In some embodiments of the process, the ratio of glycoxide to polyethylene terephthalate (PET) is between about 1:5 and about 1:20 (mol/mol).

In some embodiments of the process, the ratio of glycoxide to polyethylene terephthalate (PET) is between about 1:10 and about 1:20 (mol/mol).

In some embodiments of the process, the ratio of glycoxide to polyethylene terephthalate (PET) is between about 1:10 and about 1:15 (mol/mol).

In some embodiments of the process, the terephthalate is obtained in at least about 90 mol % yield. In some embodiments of the process, the terephthalate is obtained in at least about 95 mol % yield. In some embodiments of the process, the terephthalate is obtained in at least about 99 mol % yield.

In some embodiments of the process, the process further yields mono ethylene glycol. In some embodiments of the process, the mono ethylene glycol is obtained in at least about 80 mol % yield. In some embodiments of the process, the mono ethylene glycol is obtained in at least about 85 mol % yield.

Disclosed herein is a process for the depolymerization of polyethylene terephthalate (PET) to form a terephthalate; the process comprising:

-   -   (i) admixing the polyethylene terephthalate (PET) with a first         solvent to yield a first mixture;     -   (ii) adding a glycoxide to the first mixture;     -   (iii) adding a second solvent; and     -   (iv) admixing;     -   thereby forming the terephthalate.

In some embodiments of the process, the terephthalate is dimethyl terephthalate (DMT).

In some embodiments of the process, the first solvent is selected from methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-1,4-dimethanol, phenol, benzyl alcohol, and any combinations thereof. In some embodiments of the process, the first solvent is methanol.

In some embodiments of the process, step (i) is performed for about 15 mins to about 120 mins. In some embodiments of the process, step (i) is performed for about 60 min.

In some embodiments of the process, step (i) is performed at a temperature between about 50° C. to about 100° C. In some embodiments of the process, step (i) is performed at a temperature of about 60° C.

In some embodiments of the process, a portion of the first solvent is removed prior to step (ii) to yield a second mixture.

In some embodiments of the process, the second mixture is heated at a temperature between about 70° C. to about 100° C.

In some embodiments of the process, the second mixture is heated at a temperature of about 85° C.

In some embodiments of the process, the glycoxide is sodium glycoxide. In some embodiments of the process, the glycoxide is mono sodium glycoxide. In some embodiments of the process, the mono sodium glycoxide is provided as a suspension in a suspending solvent.

In some embodiments of the process, the mono sodium glycoxide suspension is prepared by a process comprising:

-   -   a) heating mono ethylene glycol;     -   b) adding sodium hydroxide thereby forming mono sodium         glycoxide;     -   c) drying the mono sodium glycoxide;     -   d) suspending the dried mono sodium glycoxide in a suspending         solvent; and     -   e) aging the suspension.

In some embodiments of the process, step (a) is performed at a temperature between about 70° C. to about 100° C. In some embodiments of the process, step (a) is performed at a temperature of about 90° C.

In some embodiments of the process, the ratio of mono sodium glycoxide to the suspending solvent is between about 0.05:1 to about 0.5:1 (mol/mol).

In some embodiments of the process, the ratio of mono sodium glycoxide to the suspending solvent is about 0.2:1 (mol/mol).

In some embodiments of the process, the suspending solvent is methanol.

In some embodiments of the process, the suspension is aged for about 1-14 days. In some embodiments of the process, the suspension is aged for about 1-7 days. In some embodiments of the process, the suspension is aged for about 7 days.

In some embodiments of the process, the ratio of glycoxide to polyethylene terephthalate (PET) is between about 1:2 and about 1:20 (mol/mol). In some embodiments of the process, the ratio of glycoxide to polyethylene terephthalate (PET) is between about 1:5 and about 1:20 (mol/mol). In some embodiments of the process, the ratio of glycoxide to polyethylene terephthalate (PET) is between about 1:10 and about 1:20 (mol/mol). In some embodiments of the process, the ratio of glycoxide to polyethylene terephthalate (PET) is between about 1:10 and about 1:15 (mol/mol).

In some embodiments of the process, the second solvent is selected from methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-1,4-dimethanol, phenol, benzyl alcohol, and any combinations thereof. In some embodiments of the process, the second solvent is methanol.

In some embodiments of the process, step (iv) is performed for about 60 mins to about 600 mins. In some embodiments of the process, step (iv) is performed for about 360 min.

In some embodiments of the process, step (iv) is performed at a temperature between about 70° C. to about 100° C. In some embodiments of the process, step (iv) is performed at a temperature of about 85° C.

In some embodiments of the process, the process further comprises step (v) filtrating the terephthalate.

In some embodiments of the process, the terephthalate is obtained in at least about 90 mol % yield. In some embodiments of the process, the terephthalate is obtained in at least about 95 mol % yield. In some embodiments of the process, the terephthalate is obtained in at least about 99 mol % yield.

In some embodiments of the process, the process further yields mono ethylene glycol. In some embodiments of the process, the mono ethylene glycol is obtained in at least about 80 mol % yield. In some embodiments of the process, the mono ethylene glycol is obtained in at least about 85 mol % yield.

Also disclosed herein is process for preparing a mono sodium glycoxide suspension; the process comprising:

-   -   a) heating mono ethylene glycol;     -   b) adding sodium hydroxide thereby forming mono sodium         glycoxide;     -   c) drying the mono sodium glycoxide;     -   d) suspending the dried mono sodium glycoxide into a suspending         solvent; and     -   e) aging the suspension.

In some embodiments of the process, step (a) is performed at a temperature between about 70° C. to about 100° C. In some embodiments of the process, step (a) is performed at a temperature of about 90° C.

In some embodiments of the process, the ratio of mono sodium glycoxide to the suspending solvent is between about 0.05:1 to about 0.5:1 (mol/mol). In some embodiments of the process, the ratio of mono sodium glycoxide to the suspending solvent is about 0.2:1 (mol/mol).

In some embodiments of the process, the suspending solvent is methanol.

In some embodiments of the process, the suspension is aged for about 1-14 days. In some embodiments of the process, the suspension is aged for about 1-7 days. In some embodiments of the process, the suspension is aged for about 7 days.

DETAILED DESCRIPTION OF THE INVENTION

Dimethyl terephthalate (DMT) is used in the production of polyesters, including polyethylene terephthalate (PET), polytrimethylene terephthalate (PTT), and polybutylene terephthalate (PBT). Because DMT is volatile, it is an intermediate in some schemes for the recycling of PET, e.g. from plastic bottles. Hydrogenation of DMT affords the diol 1, 4-cyclohexanedimethanol, which is a useful monomer in the formation of polyester resins.

DMT has been produced in a number of ways. Conventionally and still of commercial value is the direct esterification of terephthalic acid. Alternatively, it is prepared by alternating oxidation and methyl-esterification steps from para-xylene via methyl para-toluate. The method for the production of DMT from para-xylene and methanol consists of four major steps: oxidation, esterification, distillation, and crystallization. A mixture of p ara-xylene and pare-toluic ester is oxidized with air in the presence of a transition metal catalyst (Co/Mn). The acid mixture resulting from the oxidation is esterified with methanol to produce a mixture of esters. The crude ester mixture is distilled to remove all the heavy boilers and residue produced; the lighter esters are recycled to the oxidation section. The raw DMT is then crystallized to remove DMT isomers, residual acids, and aromatic aldehydes.

An Improvement in DMT production from PET recycling: due to the growing use of PET and PETG in the packaging and fiber (carpet and other textile) industries there is a need for an efficient, low energy, high yielding, and cost effective way to form DMT from PET or PETG.

Polyesters

Described herein is a process for the transformation of a polyester into an ester derivative; the process comprising admixing the polyester with a mixture comprising:

-   -   (a) a solvent for swelling the polyester;     -   (b) an alcoholic solvent; and     -   (c) a sub-stoichiometric amount of an alkoxide.

Described herein is a process for the transformation of a polyester into an ester derivative; the process comprising admixing the polyester with a mixture comprising a glycoxide.

In some embodiments, the polyester is selected from polyethylene terephthalate (PET), poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG), polyglycolide or polyglycolic acid (PGA), polylactic acid (PLA), polycaprolactone (PCL), polyhydroxybutyrate (PHB), polyethylene adipate (PEA), polybutylene succinate (PBS), poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV), polybutylene terephthalate (PBT), polytrimethyleneterephthalate (PTT), polyethylene naphthalate (PEN), Vectran®, cutin, and any combinations thereof.

In some embodiments, the polyester is polyethylene terephthalate (PET):

In some embodiments, the polyester is a terephthalic acid/ethylene glycol oligomer.

In some embodiments, the polyester is poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG):

In some embodiments, the polyester is polyglycolide or polyglycolic acid (PGA),

In some embodiments, the polyester is polylactic acid (PLA):

In some embodiments, the polyester is polycaprolactone (PCL):

In some embodiments, the polyester is polyhydroxybutyrate (PHB):

In some embodiments, the polyester is polyethylene adipate (PEA):

In some embodiments, the polyester is polybutylene succinate (PBS):

In some embodiments, the polyester is poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV):

In some embodiments, the polyester is polybutylene terephthalate (PBT):

In some embodiments, the polyester is polytrimethylene terephthalate (PTT):

In some embodiments, the polyester is polyethylene naphthalate (PEN):

In some embodiments, the polyester is Vectran®:

In some embodiments, the polyester is cutin. Cutin is one of two waxy polymers that are the main components of the plant cuticle, which covers all aerial surfaces of plants. Cutin consists of omega hydroxy acids and their derivatives, which are interlinked via ester bonds, forming a polyester polymer. There are two major monomer families of cutin, the C16 and C18 families. The C16 family consists mainly of 16-hydroxy palmitic acid and 9,16- or 10,16-dihydroxypalmitic acid. The C18 family consists mainly of 18-hydroxy oleic acid, 9,10-epoxy-18-hydroxy stearic acid, and 9,10,18-trihydroxystearate. Tomato cutin consists of 16-hydroxy palmitic acid and 10,16-dihydroxypalmitic acid where the 10-isomer is largely dominant. The tomato cutin is a polyester biopolymer interesterificated. The significant proportion of secondary esters (esterification in the C-10 secondary hydroxyl) shows that the polyester structure is significantly branched.

Ester Derivatives

Described herein is a process for the transformation of a polyester into an ester derivative; the process comprising admixing the polyester with a mixture comprising:

-   -   (a) a solvent for swelling the polyester;     -   (b) an alcoholic solvent; and     -   (c) a sub-stoichiometric amount of an alkoxide.

Described herein is a process for the transformation of a polyester into an ester derivative; the process comprising admixing the polyester with a mixture comprising a glycoxide.

In some embodiments, the polyester is polyglycolide or polyglycolic acid (PGA) and the ester derivative is a 2-hydroxyacetate derivative. In some embodiments, the ester derivative is methyl 2-hydroxyacetate.

In some embodiments, the polyester is polylactic acid (PLA) and the ester derivative is a 2-hydroxypropanoate derivative. In some embodiments, the ester derivative is methyl 2-hydroxypropanoate.

In some embodiments, the polyester is polycaprolactone (PCL) and the ester derivative is a 6-hydroxyhexanoate derivative. In some embodiments, the ester derivative is a methyl 6-hydroxyhexanoate.

In some embodiments, the polyester is polyhydroxybutyrate (PHB) and the ester derivative is a hydroxybutyrate derivative. In some embodiments, the ester derivative is methyl hydroxybutyrate.

In some embodiments, the polyester is polyethylene adipate (PEA) and the ester derivative is an adipate derivative. In some embodiments, the ester derivative is dimethyl adipate.

In some embodiments, the polyester is polybutylene succinate (PBS) and the ester derivative is a succinate derivative. In some embodiments, the ester derivative is dimethyl succinate.

In some embodiments, the polyester is poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) and the ester derivative is a hydroxybutyrate derivative, a hydroxyvalerate derivative, or a combination thereof. In some embodiments, the ester derivative is methyl hydroxybutyrate, methyl hydroxyvalerate, or a combination thereof.

In some embodiments, the polyester is polyethylene naphthalate (PEN) and the ester derivative is a naphthalate derivative. In some embodiments, the ester derivative is dimethyl naphthalate.

In some embodiments, the polyester is vectran and the ester derivative is a naphthoate derivative, a benzoate derivative, or a combination thereof. In some embodiments, the ester derivative is methyl hydroxynaphthoate or methyl hydroxybenzoate.

In some embodiments, the polyester is cutin and the ester derivative is a hydroxypalmitate or a dihydroxypalmitate derivative. In some embodiments, the ester derivative is methyl hydroxypalmitate or methyl dihydroxypalmitate.

In some embodiments, the polyester is polyethylene terephthalate (PET), poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG), polytrimethylene terephthalate (PTT), or polybutylene terephthalate (PBT) and the ester derivative is a terephthalate. In some embodiments, the terephthalate is dimethyl terephthalate. In some embodiments, the terephthalate is diethyl terephthalate.

In some embodiments, the polyester is polyethylene terephthalate (PET), poly(ethylene glycol-co-1,4-cyclohexanedimethanol terephthalate) (PETG), polytrimethylene terephthalate (PTT), or polybutylene terephthalate (PBT) and the ester derivative is a terephthalate derivative. In some embodiments, the terephthalate derivative is a compound of formula (I):

-   -   wherein R¹ and R² are independently selected from hydrogen,         C₁-C₆ alkyl, C₁-C₆haloalkyl, C₁-C₆ hydroxyalkyl, optionally         substituted C₃-C₈ cycloalkyl, optionally substituted (C₁-C₆         alkyl)(C₃-C₈ cycloalkyl), optionally substituted aryl, and         optionally substituted (C₁-C₆ alkyl)(aryl); provided that one of         R¹ or R² is not hydrogen.

In some embodiments of a compound of Formula (I), R¹ and R² are independently C₁-C₆ alkyl or C₁-C₆ hydroxyalkyl.

In some embodiments of a compound of Formula (I), R¹ and R² are independently C₁-C₆ alkyl. In some embodiments of a compound of Formula (I), R¹ and R² are independently methyl, ethyl, propyl, isopropyl, or butyl. In some embodiments of a compound of Formula (I), R¹ and R² are independently methyl or ethyl. In some embodiments of a compound of Formula (I), R¹ and R² are methyl. In some embodiments of a compound of Formula (I), R¹ and R² are ethyl. In some embodiments of a compound of Formula (I), R¹ and R² are not hydrogen.

In some embodiments of a compound of Formula (I), R¹ and R² are independently C₁-C₆ hydroxyalkyl. In some embodiments of a compound of Formula (I), R¹ and R² are independently hydroxyethyl or propanediol. In some embodiments of a compound of Formula (I), R¹ and R² are hydroxyethyl. In some embodiments of a compound of Formula (I), R¹ and R² are 2-hydroxyethyl. In some embodiments of a compound of Formula (I), R¹ and R² are dihydroxypropyl. In some embodiments of a compound of Formula (I), R¹ and R² are 2,3-dihydroxypropyl.

In some embodiments of a compound of Formula (I), R¹ and R² are independently optionally substituted (C₁-C₆ alkyl)(C₃-C₈ cycloalkyl). In some embodiments of a compound of Formula (I), R¹ and R² are independently substituted (C₁-C₆ alkyl)(C₃-C₈ cycloalkyl). In some embodiments of a compound of Formula (I), R¹ and R² are 4-(hydroxymethyl)cyclohexyl)methyl.

In some embodiments of a compound of Formula (I), R¹ and R² are independently optionally substituted aryl. In some embodiments of a compound of Formula (I), 10 and R² are phenyl.

In some embodiments of a compound of Formula (I), R¹ and R² are independently optionally substituted (C₁-C₆ alkyl)(aryl). In some embodiments of a compound of Formula (I), R¹ and R² are benzyl.

In some embodiments, the ester derivative contains less than about 10% impurity (w/w). In some embodiments, the ester derivative contains less than about 9% impurity (w/w). In some embodiments, the ester derivative contains less than about 8% impurity (w/w). In some embodiments, the ester derivative contains less than about 7% impurity (w/w). In some embodiments, the ester derivative contains less than about 6% impurity (w/w). In some embodiments, the ester derivative contains less than about 5% impurity (w/w). In some embodiments, the ester derivative contains less than about 4% impurity (w/w). In some embodiments, the ester derivative contains less than about 3% impurity (w/w). In some embodiments, the ester derivative contains less than about 2% impurity (w/w). In some embodiments, the ester derivative contains less than about 1% impurity (w/w). In some embodiments, the ester derivative contains less than about 0.5% impurity (w/w). In some embodiments, the ester derivative contains less than about 0.4% impurity (w/w). In some embodiments, the ester derivative contains less than about 0.3% impurity (w/w). In some embodiments, the ester derivative contains less than about 0.2% impurity (w/w). In some embodiments, the ester derivative contains less than about 0.1% impurity (w/w).

In some embodiments, the ester derivative contains less than about 250 ppm of any metals, less than about 240 ppm of any metals, less than about 230 ppm of any metals, less than about 220 ppm of any metals, less than about 210 ppm of any metals, less than about 200 ppm of any metals, less than about 190 ppm of any metals, less than about 180 ppm of any metals, less than about 170 ppm of any metals, less than about 160 ppm of any metals, less than about 150 ppm of any metals, less than about 140 ppm of any metals, less than about 130 ppm of any metals, less than about 120 ppm of any metals, less than about 110 ppm of any metals, less than about 100 ppm of any metals, less than about 90 ppm of any metals, less than about 80 ppm of any metals, less than about 70 ppm of any metals, less than about 60 ppm of any metals, less than about 50 ppm of any metals, less than about 40 ppm of any metals, less than about 30 ppm of any metals, less than about 20 ppm of any metals, less than about 10 ppm of any metals, less than about 5 ppm of any metals, less than about 4 ppm of any metals, less than about 3 ppm of any metals, less than about 2 ppm of any metals, less than about 1 ppm of any metals, less than about 0.9 ppm of any metals, less than about 0.8 ppm of any metals, less than about 0.7 ppm of any metals, less than about 0.6 ppm of any metals, less than about 0.5 ppm of any metals, less than about 0.4 ppm of any metals, less than about 0.3 ppm of any metals, less than about 0.2 ppm of any metals, less than about 0.1 ppm of any metals, less than about 0.09 ppm of any metals, less than about 0.08 ppm of any metals, less than about 0.07 ppm of any metals, less than about 0.06 ppm of any metals, less than about 0.05 ppm of any metals, less than about 0.04 ppm of any metals, less than about 0.03 ppm of any metals, less than about 0.02 ppm of any metals, or less than about 0.01 ppm of any metals.

In some embodiments, the ester derivative contains less than about 10 ppm of glycoxide, less than about 5 ppm of glycoxide, less than about 4 ppm of glycoxide, less than about 3 ppm of glycoxide, less than about 2 ppm of glycoxide, less than about 1 ppm of glycoxide, less than about 0.9 ppm of glycoxide, less than about 0.8 ppm of glycoxide, less than about 0.7 ppm of glycoxide, less than about 0.6 ppm of glycoxide, less than about 0.5 ppm of glycoxide, less than about 0.4 ppm of glycoxide, less than about 0.3 ppm of glycoxide, less than about 0.2 ppm of glycoxide, less than about 0.1 ppm of glycoxide, less than about 0.09 ppm of glycoxide, less than about 0.08 ppm of glycoxide, less than about 0.07 ppm of glycoxide, less than about 0.06 ppm of glycoxide, less than about 0.05 ppm of glycoxide, less than about 0.04 ppm of glycoxide, less than about 0.03 ppm of glycoxide, less than about 0.02 ppm of glycoxide, or less than about 0.01 ppm of glycoxide.

In some embodiments, the ester derivative is obtained in between about 80 and about 99 mol % yield. In some embodiments, the ester derivative is obtained in between about 85 and about 99 mol % yield. In some embodiments, the ester derivative is obtained in between about 90 and about 99 mol % yield. In some embodiments, the ester derivative is obtained in at least about 90 mol % yield. In some embodiments, the ester derivative is obtained in at least about 95 mol % yield. In some embodiments, the ester derivative is obtained in at least about 99 mol % yield.

In some embodiments, the terephthalate is obtained in between about 80 and about 99 mol % yield. In some embodiments, the terephthalate is obtained in between about 85 and about 99 mol % yield. In some embodiments, the terephthalate is obtained in between about 90 and about 99 mol % yield. In some embodiments, the terephthalate is obtained in at least about 80 mol % yield. In some embodiments, the terephthalate is obtained in at least about 85 mol % yield. In some embodiments, the terephthalate is obtained in at least about 90 mol % yield. In some embodiments, the terephthalate is obtained in at least about 95 mol % yield. In some embodiments, the terephthalate is obtained in at least about 99 mol % yield.

Glycol

Described herein is a process for the transformation of a polyester into an ester derivative and a glycol; the process comprising admixing the polyester with a mixture comprising a glycoxide. In some embodiments, the glycol is mono ethylene glycol (MEG) (or ethylene glycol). In some embodiments, the glycol is propylene glycol. In some embodiments, the glycol is butylene glycol.

In some embodiments, the glycol is obtained in between about 80 and about 99 mol % yield. In some embodiments, the glycol is obtained in between about 85 and about 99 mol % yield. In some embodiments, the glycol is obtained in between about 90 and about 99 mol % yield. In some embodiments, the glycol is obtained in at least about 80 mol % yield. In some embodiments, the glycol is obtained in at least about 85 mol % yield. In some embodiments, the glycol is obtained in at least about 90 mol % yield. In some embodiments, the glycol is obtained in at least about 95 mol % yield.

Glycoxide

In some embodiments, the process described herein comprises an alkoxide which is derived from an alcohol with a boiling point higher than water. In some embodiments, the alcohol is mono ethylene glycol (MEG), glycerol, sorbitol, 1,3-propanediol, or cyclohexane-1,4-dimethanol In some embodiments, the alcohol is mono ethylene glycol (MEG).

In some embodiments, the process described herein comprises an alkoxide which is cost efficient. In some embodiments, the process described herein comprises the use of an alkoxide in an amount that provides a cost savings compared to other catalysts such as sodium methoxide as a weight-weight ratio. In some embodiments, the process described herein comprises the use of sodium glycoxide in an amount that provides a cost savings compared to other catalysts such as sodium methoxide as a weight-weight ratio. In some embodiments, the process described herein comprises an alkoxide that is able to undergo an exchange with methanol to results in sodium methoxide.

In some embodiments, the process described herein comprises a glycoxide. In some embodiments, the process described herein comprises a catalytic amount of a glycoxide. In some embodiments, the process described herein comprises a sub-stoichiometric amount of a glycoxide.

“Sub-stoichiometric amount”, as used herein, is used to indicate that the amount of material used is less than a stoichiometric amount. The term is used herein interchangeably with “catalytic amount.” In some embodiments, a sub-stoichiometric amount is less than or equal to about 95% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 90% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 85% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 80% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 75% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 70% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 65% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 60% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 55% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 50% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 45% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 40% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 35% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 30% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 25% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 20% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 15% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 10% of a stoichiometric amount.

“Stoichiometric amount”, as used herein, is used to indicate that the amount of material used is equivalent to the number of ester linkages present in the polyester.

In some embodiments, the glycoxide, which comprises a glycoxide anion and a cation, is selected from an alkali metal glycoxide, an alkaline earth metal glycoxide, a metal glycoxide, an ammonium glycoxide, and any combinations thereof. In some embodiments, the cation is lithium, sodium, potassium, magnesium, calcium, strontium, barium, zinc, aluminum, or ammonium. In some embodiments, the glycoxide is sodium glycoxide. In some embodiments, the glycoxide is mono sodium glycoxide.

In some embodiments, the glycoxide is generated by addition of an alkali metal, an alkaline earth metal, or a metal to mono ethylene glycol (MEG). In some embodiments, the glycoxide is generated by addition of sodium hydroxyde to mono ethylene glycol (MEG).

In some embodiments, the glycoxide is provided as a suspension.

Disclosed herein is a process for preparing a mono sodium glycoxide suspension, the process comprising:

-   -   a) heating mono ethylene glycol;     -   b) adding sodium hydroxide thereby forming mono sodium         glycoxide;     -   c) drying the mono sodium glycoxide;     -   d) suspending the dried mono sodium glycoxide into a suspending         solvent; and     -   e) aging the suspension.

In some embodiments, the suspending solvent is an alcohol. In some embodiments, the suspending solvent is methanol.

In some embodiments, step (a) is performed at a temperature between about 70° C. to about 100° C. In some embodiments, step (a) is performed at a temperature between about 70° C. to about 90° C. In some embodiments, step (a) is performed at a temperature between about 80° C. to about 100° C. In some embodiments, step (a) is performed at a temperature of about 70° C., about 75° C., about 80° C., about 85° C., about 90° C., about 95° C., or about 100° C. In some embodiments, step (a) is performed at a temperature of about 90° C.

In some embodiments, the ratio of mono sodium glycoxide to the suspending solvent is between about 0.05:1 to about 0.5:1 (mol/mol). In some embodiments, the ratio of mono sodium glycoxide to the suspending solvent is between about 0.1:1 to about 0.5:1 (mol/mol). In some embodiments, the ratio of mono sodium glycoxide to the suspending solvent is between about 0.1:1 to about 0.3:1 (mol/mol). In some embodiments, the ratio of mono sodium glycoxide to the suspending solvent is about 0.05:1 (mol/mol), about 0.06:1 (mol/mol), about 0.07:1 (mol/mol), about 0.08:1 (mol/mol), about 0.09:1 (mol/mol), about 0.1:1 (mol/mol), about 0.11:1 (mol/mol), about 0.12:1 (mol/mol), about 0.13:1 (mol/mol), about 0.14:1 (mol/mol), about 0.15:1 (mol/mol), about 0.16:1 (mol/mol), about 0.17:1 (mol/mol), about 0.18:1 (mol/mol), about 0.19:1 (mol/mol), about 0.2:1 (mol/mol), about 0.21:1 (mol/mol), about 0.22:1 (mol/mol), about 0.23:1 (mol/mol), about 0.24:1 (mol/mol), about 0.25:1 (mol/mol), about 0.26:1 (mol/mol), about 0.27:1 (mol/mol), about 0.28:1 (mol/mol), about 0.29:1 (mol/mol), about 0.30:1 (mol/mol), about 0.35:1 (mol/mol), about 0.40:1 (mol/mol), about 0.45:1 (mol/mol), or about 0.5:1 (mol/mol). In some embodiments, the ratio of mono sodium glycoxide to the suspending solvent is about 0.2:1 (mol/mol).

In some embodiments, the ratio of glycoxide to polyethylene terephthalate (PET) is between about 1:2 and about 1:20 (mol/mol). In some embodiments, the ratio of glycoxide to polyethylene terephthalate (PET) is between about 1:2 and about 1:10 (mol/mol). In some embodiments, the ratio of glycoxide to polyethylene terephthalate (PET) is between about 1:2 and about 1:6 (mol/mol). In some embodiments, the ratio of glycoxide to polyethylene terephthalate (PET) is between about 1:5 and about 1:20 (mol/mol). In some embodiments, the ratio of glycoxide to polyethylene terephthalate (PET) is between about 1:10 and about 1:20 (mol/mol). In some embodiments, the ratio of glycoxide to polyethylene terephthalate (PET) is between about 1:10 and about 1:15 (mol/mol). In some embodiments, the ratio of glycoxide to polyethylene terephthalate (PET) is about 1:2 (mol/mol), about 1:3 (mol/mol), about 1:4 (mol/mol), about 1:5 (mol/mol), about 1:6 (mol/mol), about 1:7 (mol/mol), about 1:8 (mol/mol), about 1:9 (mol/mol), about 1:10 (mol/mol), about 1:11 (mol/mol), about 1:12 (mol/mol), about 1:13 (mol/mol), about 1:14 (mol/mol), about 1:15 (mol/mol), about 1:16 (mol/mol), about 1:17 (mol/mol), about 1:18 (mol/mol), about 1:19 (mol/mol), or about 1:2 (mol/mol).

In some embodiments, the mono sodium glycoxide is dried to remove water formed during the reaction. In some embodiments, the mono sodium glycoxide is dried at a temperature higher than the boiling point of water. In some embodiments, the mono sodium glycoxide is dried at a temperature between about 100° C. and about 150° C. In some embodiments, the mono sodium glycoxide is dried at a temperature between about 110° C. and about 140° C. In some embodiments, the mono sodium glycoxide is dried at a temperature between about 120° C. and about 130° C. In some embodiments, the mono sodium glycoxide is dried at a temperature of about 100° C., about 105° C., about 110° C., about 115° C., about 120° C., about 125° C., about 130° C., about 135° C., about 140° C., about 145° C., or about 150° C. In some embodiments, the mono sodium glycoxide is dried at about 130° C.

In some embodiments, the suspension is aged for about 1 day to about 2 months. In some embodiments, the suspension is aged for about 1-14 days. In some embodiments, the suspension is aged for about 7-14 days. In some embodiments, the suspension is aged for about 5-8 days. In some embodiments, the suspension is aged for about 1-7 days. In some embodiments, the suspension is aged for about 1 day, about 2 days, about 3 days, about 4 days, about 5 days, about 6 days, about 7 days, about 8 days, about 9 days, about 10 days, about 11 days, about 12 days, about 13 days, or about 14 days. In some embodiments, the suspension is aged for about 7 days. In some embodiments, “aged” as used herein means stored at room temperature and ambient pressure. In some embodiments, the aging step allows for a fraction of the sodium glycoxide to convert to sodium methoxide. In some embodiments, the aged glycoxide suspension comprises up to about 85% of sodium methoxide. In some embodiments, the aged glycoxide suspension comprises up to about 85%, up to about 80%, up to about 75%, up to about 70%, up to about 65%, up to about 60%, up to about 55%, up to about 50%, up to about 45%, up to about 40%, up to about 45%, up to about 40%, up to about 35%, up to about 30%, up to about 25%, up to about 20%, up to about 15%, up to about 10%, or up to about 5% of sodium methoxide.

Depolymerization

Described herein is a process for the transformation of a polyester into an ester derivative; the process comprising admixing the polyester with a mixture comprising a glycoxide. Described herein is process for the depolymerization of polyethylene terephthalate (PET) to form a terephthalate; the process comprising admixing polyethylene terephthalate (PET) with a mixture comprising a glycoxide.

In some embodiments, the mixture further comprises a solvent.

In some embodiments, the solvent comprises a linear alcohol, branched alcohol, cyclic alcohol, or any combinations thereof. In some embodiments, the solvent is selected from methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-1,4-dimethanolphenol, benzyl alcohol, and any combinations thereof.

In some embodiments, the solvent is a linear C₁-C₄ alcohol. In some embodiments, the solvent is methanol, ethanol, propanol, butanol, or a combination thereof. In some embodiments, the solvent is methanol, ethanol, propanol, or a combination thereof. In some embodiments, the solvent is methanol. In some embodiments, the alcohol is ethanol. In some embodiments, the solvent is a branched C₃-C₄ alcohol. In some embodiments, the solvent is t-butanol, s-butanol, butanol, i-propanol, or any combinations thereof. In some embodiments, the solvent is a cyclic C₃-C₈ alcohol. In some embodiments, the solvent is cyclopropanol, cyclobutanol, cyclopentanol, cyclohexanol, cycloheptanol, cyclohexane-1,4-dimethanol, or any combinations thereof. In some embodiments, the solvent is cyclohexane-1,4-dimethanol.

In some embodiments, the solvent is a polyol. In some embodiments, the solvent is selected from ethylene glycol, glycerol, and any combinations thereof. In some embodiments, the solvent is selected from phenol, benzyl alcohol, and any combinations thereof.

In some embodiments, the solvent is added to the polyethylene terephthalate (PET) prior to the addition of the glycoxide. In some embodiments, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide for about 15 mins to about 120 mins. In some embodiments, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide for about 15 mins to about 90 mins. In some embodiments, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide for about 30 mins to about 90 mins. In some embodiments, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide for about 45 mins to about 90 mins. In some embodiments, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide for about 15 mins, about 20 mins, about 25 mins, about 30 mins, about 35 mins, about 40 mins, about 45 mins, about 50 mins, about 55 mins, about 60 mins, about 65 mins, about 70 mins, about 75 mins, about 80 mins, about 85 mins, about 90 mins, about 95 mins, about 100 mins, about 105 mins, about 110 mins, about 115 mins, or about 120 mins. In some embodiments, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide for about 60 min.

In some embodiments, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide and heated to a temperature between about 50° C. to about 100° C. In some embodiments, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide and heated to a temperature between about 50° C. to about 90° C. In some embodiments, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide and heated to a temperature between about 50° C. to about 80° C. In some embodiments, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide and heated to a temperature between about 50° C. to about 70° C. In some embodiments, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide and heated to a temperature of about 50° C., about 55° C., about 60° C., about 65° C., about 70° C., about 75° C., about 80° C., about 85° C., about 90° C., about 95° C., or about 100° C. In some embodiments, the polyethylene terephthalate (PET) is mixed with the solvent prior to the addition of the glycoxide and heated to a temperature of about 60° C.

Described herein is a process for the transformation of a polyester into an ester derivative; the process comprising:

-   -   (i) admixing the polyethylene terephthalate (PET) with a first         solvent to yield a first mixture;     -   (ii) adding a glycoxide to the first mixture;     -   (iii) adding a second solvent; and     -   (iv) admixing;     -   thereby forming the ester derivative.

Also described herein is a process for the depolymerization of polyethylene terephthalate (PET) to form a terephthalate; the process comprising:

-   -   admixing the polyethylene terephthalate (PET) with a first         solvent to yield a first mixture;     -   (ii) adding a glycoxide to the first mixture;     -   (iii) adding a second solvent; and     -   (iv) admixing;     -   thereby forming the terephthalate.

In some embodiments, the first solvent comprises a linear alcohol, branched alcohol, cyclic alcohol, or any combinations thereof. In some embodiments, the first solvent is selected from methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-1,4-dimethanol, phenol, benzyl alcohol, and any combinations thereof.

In some embodiments, the first solvent is a linear C₁-C₄ alcohol. In some embodiments, the first solvent is methanol, ethanol, propanol, butanol, or a combination thereof. In some embodiments, the first solvent is methanol, ethanol, propanol, or a combination thereof. In some embodiments, the first solvent is methanol. In some embodiments, the alcohol is ethanol. In some embodiments, the first solvent is a branched C₃-C₄ alcohol. In some embodiments, the first solvent is t-butanol, s-butanol, i-butanol, i-propanol, or any combinations thereof. In some embodiments, the first solvent is a cyclic C₃-C₈ alcohol. In some embodiments, the first solvent is cyclopropanol, cyclobutanol, cyclopentanol, cyclohexanol, cycloheptanol, cyclohexane-1,4-dimethanol, or any combinations thereof. In some embodiments, the first solvent is cyclohexane-1,4-dimethanol.

In some embodiments, the first solvent is a polyol. In some embodiments, the first solvent is selected from ethylene glycol, glycerol, and any combinations thereof. In some embodiments, the first solvent is selected from phenol, benzyl alcohol, and any combinations thereof.

In some embodiments, step (i) is performed for about 15 mins to about 120 mins. In some embodiments, step (i) is performed for about 15 mins to about 90 mins. In some embodiments, step (i) is performed for about 30 mins to about 90 mins. In some embodiments, step (i) is performed for about 45 mins to about 90 mins. In some embodiments, step (i) is performed for about 15 mins, about 20 mins, about 25 mins, about 30 mins, about 35 mins, about 40 mins, about 45 mins, about 50 mins, about 55 mins, about 60 mins, about 65 mins, about 70 mins, about 75 mins, about 80 mins, about 85 mins, about 90 mins, about 95 mins, about 100 mins, about 105 mins, about 110 mins, about 115 mins, or about 120 mins. In some embodiments, step (i) is performed for about 60 mins.

In some embodiments, step (i) is performed at a temperature between about 50° C. to about 100° C. In some embodiments, step (i) is performed at a temperature between about 50° C. to about 90° C. In some embodiments, step (i) is performed at a temperature between about 50° C. to about 80° C. In some embodiments, step (i) is performed at a temperature between about 50° C. to about 70° C. In some embodiments, step (i) is performed at a temperature of about 50° C., about 55° C., about 60° C., about 65° C., about 70° C., about 75° C., about 80° C., about 85° C., about 90° C., about 95° C., or about 100° C. In some embodiments, step (i) is performed at a temperature of about 60° C.

In some embodiments, a portion of the first solvent is removed prior to step (ii) to yield a second mixture. In some embodiments, the removal of a portion of the first solvent allows for the removal of the water trapped in the polyethylene terephthalate (PET) feedstock. In some embodiments, between about 1 mol and about 5 mol of first solvent is removed per mol of PET. In some embodiments, between about 1 mol and about 3 mol of first solvent is removed per mol of PET. In some embodiments, between about 2 mol and about 4 mol of first solvent is removed per mol of PET. In some embodiments, about 1 mol, about 1.1 mol, about 1.2 mol, about 1.3 mol, about 1.4 mol, about 1.5 mol, about 1.6 mol, about 1.7 mol, about 1.8 mol, about 1.9 mol, about 2 mol, about 2.1 mol, about 2.2 mol, about 2.3 mol, about 2.4 mol, about 2.5 mol, about 2.6 mol, about 2.7 mol, about 2.8 mol, about 2.9 mol, about 3 mol, about 3.1 mol, about 3.2 mol, about 3.3 mol, about 3.4 mol, about 3.5 mol, about 3.6 mol, about 3.7 mol, about 3.8 mol, about 3.9 mol, about 4 mol, about 4.1 mol, about 4.2 mol, about 4.3 mol, about 4.4 mol, about 4.5 mol, about 4.6 mol, about 4.7 mol, about 4.8 mol, about 4.9 mol, or about 5 mol of first solvent is removed per mol of PET.

In some embodiments, the second mixture is heated at a temperature between about 70° C. to about 100° C. In some embodiments, the second mixture is heated at a temperature between about 80° C. to about 100° C. In some embodiments, the second mixture is heated at a temperature between about 70° C. to about 90° C. In some embodiments, the second mixture is heated at a temperature of about 70° C., about 75° C., about 80° C., about 85° C., about 90° C., about 95° C., or about 100° C. In some embodiments, the second mixture is heated at a temperature of about 85° C.

In some embodiments, the second solvent comprises a linear alcohol, branched alcohol, cyclic alcohol, or any combinations thereof. In some embodiments, the second solvent is selected from methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-1,4-dimethanol, phenol, benzyl alcohol, and any combinations thereof.

In some embodiments, the second solvent is a linear C₁-C₄ alcohol. In some embodiments, the second solvent is methanol, ethanol, propanol, butanol, or a combination thereof. In some embodiments, the second solvent is methanol, ethanol, propanol, or a combination thereof. In some embodiments, the second solvent is methanol. In some embodiments, the alcohol is ethanol. In some embodiments, the second solvent is a branched C₃-C₄ alcohol. In some embodiments, the second solvent is t-butanol, s-butanol, i-butanol, propanol, or any combinations thereof. In some embodiments, the second solvent is a cyclic C₃-C₈ alcohol. In some embodiments, the second solvent is cyclopropanol, cyclobutanol, cyclopentanol, cyclohexanol, cycloheptanol, cyclohexane-1,4-dimethanol, or any combinations thereof. In some embodiments, the second solvent is cyclohexane-1,4-dimethanol. In some embodiments, the second solvent is a polyol. In some embodiments, the second solvent is selected from ethylene glycol, glycerol, and any combinations thereof. In some embodiments, the second solvent is selected from phenol, benzyl alcohol, and any combinations thereof.

In some embodiments, step (iv) is performed for about 60 mins to about 600 mins. In some embodiments, step (iv) is performed for about 120 mins to about 600 mins. In some embodiments, step (iv) is performed for about 180 mins to about 600 mins. In some embodiments, step (iv) is performed for about 60 mins to about 480 mins. In some embodiments, step (iv) is performed for about 180 mins to about 480 mins. In some embodiments, step (iv) is performed for about 60 mins, 90 mins, 120 mins, 180 mins, 240 mins, 300 mins, 360 mins, 420 mins, 480 mins, 540 mins, or 600 mins. In some embodiments, step (iv) is performed for about 360 min.

In some embodiments, step (iv) is performed at a temperature between about 70° C. to about 100° C. In some embodiments, step (iv) is performed at a temperature between about 70° C. to about 90° C. In some embodiments, step (iv) is performed at a temperature between about 80° C. to about 100° C. In some embodiments, step (iv) is performed at a temperature of about 70° C., about 75° C., about 80° C., about 85° C., about 90° C., about 95° C., or about 100° C. In some embodiments, step (iv) is performed at a temperature of about 85° C.

In some embodiments, the process further comprises step (v) filtrating the terephthalate.

In some embodiments, the process further comprises step (vi) distilling the terephthalate. Alternatively, in some embodiments, the process further comprises step (vi) subliming the terephthalate.

Also described herein is a process for the depolymerization of polyethylene terephthalate (PET) to form a terephthalate; the process comprising:

-   -   (i) admixing the polyethylene terephthalate (PET) with a first         solvent to yield a first mixture;     -   (ii) adding a glycoxide to the first mixture;     -   (iii) adding a second solvent;     -   (iv) admixing; and     -   (v) filtrating the terephthalate;     -   thereby isolating the terephthalate.

Also described herein is a process for the depolymerization of polyethylene terephthalate (PET) to form a terephthalate; the process comprising:

-   -   (i) admixing the polyethylene terephthalate (PET) with a first         solvent to yield a first mixture;     -   (ii) adding a glycoxide to the first mixture;     -   (iii) adding a second solvent;     -   (iv) admixing;     -   (v) filtrating the terephthalate; and     -   (vi) distilling the terephthalate;     -   thereby isolating pure terephthalate.

Also described herein is a process for the depolymerization of polyethylene terephthalate (PET) to form a terephthalate; the process comprising:

-   -   (i) admixing the polyethylene terephthalate (PET) with a first         solvent to yield a first mixture;     -   (ii) adding a glycoxide to the first mixture;     -   (iii) adding a second solvent;     -   (iv) admixing;     -   (v) filtrating the terephthalate; and     -   (vi) subliming the terephthalate;     -   thereby isolating pure terephthalate.

Also described herein is a process for the depolymerization of polyethylene terephthalate (PET) to form a terephthalate; the process comprising:

-   -   (i) admixing the polyethylene terephthalate (PET) with a first         solvent to yield a first mixture;     -   (ii) removing a portion of the first solvent from the first         mixture to yield a second mixture;     -   (iii) adding a glycoxide to the second mixture;     -   (iv) adding a second solvent; and     -   (v) admixing;     -   thereby forming the terephthalate.

Also described herein is a process for the depolymerization of polyethylene terephthalate (PET) to form a terephthalate; the process comprising:

-   -   (i) admixing the polyethylene terephthalate (PET) with a first         solvent to yield a first mixture;     -   (ii) removing a portion of the second solvent from the first         mixture to yield a second mixture;     -   (iii) adding a glycoxide to the second mixture;     -   (iv) adding a second solvent;     -   (v) admixing; and     -   (vi) filtrating the terephthalate;     -   thereby isolating the terephthalate.

Also described herein is a process for the depolymerization of polyethylene terephthalate (PET) to form a terephthalate; the process comprising:

-   -   (i) admixing the polyethylene terephthalate (PET) with a first         solvent to yield a first mixture;     -   (ii) removing a portion of the second solvent from the first         mixture to yield a second mixture;     -   (iii) adding a glycoxide to the second mixture;     -   (iv) adding a second solvent;     -   (v) admixing;     -   (vi) filtrating the terephthalate; and     -   (vii) distilling the terephthalate;     -   thereby isolating pure terephthalate.

Also described herein is a process for the depolymerization of polyethylene terephthalate (PET) to form a terephthalate; the process comprising:

-   -   (i) admixing the polyethylene terephthalate (PET) with a first         solvent to yield a first mixture;     -   (ii) removing a portion of the second solvent from the first         mixture to yield a second mixture;     -   (iii) adding a glycoxide to the second mixture;     -   (iv) adding a second solvent;     -   (v) admixing;     -   (vi) filtrating the terephthalate; and     -   (vii) subliming the terephthalate;     -   thereby isolating pure terephthalate.

Alcoholic Solvent

Described herein is a process for the transformation of a polyester into an ester derivative; the process comprising admixing the polyester with a mixture comprising:

-   -   (a) a solvent for swelling the polyester;     -   (b) an alcoholic solvent; and     -   (c) a sub-stoichiometric amount of an alkoxide.

In some embodiments, the process described herein comprises an alcoholic solvent. In some embodiments, the alcoholic solvent is a linear alcohol, branched alcohol, cyclic alcohol, or any combinations thereof. In some embodiments, the alcoholic solvent is selected from methanol, ethanol, n-propanol, isopropanol, t-butanol, ethylene glycol, glycerol, cyclohexane-1,4-diyldimethanol, phenol, benzyl alcohol, and any combinations thereof.

In some embodiments, the alcoholic solvent is a linear C₁-C₄ alcohol. In some embodiments, the alcoholic solvent is methanol, ethanol, propanol, butanol, or a combination thereof. In some embodiments, the alcoholic solvent is methanol, ethanol, propanol, or a combination thereof. In some embodiments, the alcoholic solvent is methanol. In some embodiments, the alcohol is ethanol. In some embodiments, the alcoholic solvent is a branched C₃-C₄ alcohol. In some embodiments, the alcoholic solvent is t-butanol, s-butanol, i-butanol, propanol, or any combinations thereof. In some embodiments, the alcoholic solvent is a cyclic C₃-C₈ alcohol. In some embodiments, the alcoholic solvent is cyclopropanol, cyclobutanol, cyclopentanol, cyclohexanol, cycloheptanol, cyclohexane-1,4-diyldimethanol, or any combinations thereof. In some embodiments, the alcoholic solvent is cyclohexane-1,4-diyldimethanol.

In some embodiments, the alcoholic solvent is a polyol. In some embodiments, the alcoholic solvent is selected from ethylene glycol, glycerol, and any combinations thereof.

In some embodiments, the alcoholic solvent is selected from phenol, benzyl alcohol, and any combinations thereof.

Solvent for Swelling the Polyester

Described herein is a process for the transformation of a polyester into an ester derivative; the process comprising admixing the polyester with a mixture comprising:

-   -   (a) a solvent for swelling the polyester;     -   (b) an alcoholic solvent; and     -   (c) a sub-stoichiometric amount of an alkoxide.

In some embodiments, the process described herein comprises pre-treating the polyester with a solvent for swelling the polyester prior to the addition of the alcoholic solvent and alkoxide. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for between about 5 mins and about 60 mins prior to the addition of the alcoholic solvent and alkoxide. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for between about 5 mins and about 40 mins prior to the addition of the alcoholic solvent and alkoxide. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for between about 5 mins and about 20 mins prior to the addition of the alcoholic solvent and alkoxide. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for between about 5 mins and about 10 mins prior to the addition of the alcoholic solvent and alkoxide. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 5 mins. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 10 mins. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 15 mins. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 20 mins. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 25 mins. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 30 mins. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 35 mins. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 40 mins. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 45 mins. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 50 mins. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 55 mins. In some embodiments, the pre-treatment with the solvent for swelling the polyester is done for about 60 mins.

In some embodiments, the process described herein comprises treating the polyester with a solvent for swelling the polyester at the same time as the addition of the alcoholic solvent and alkoxide.

In some embodiments, the solvent for swelling the polyester is selected from a non polar solvent, a polar aprotic solvent, a polar protic solvent, and any combinations thereof.

In some embodiments, the solvent for swelling the polyester is selected from dimethyl sulfoxide (DMSO), N,N-dimethylformamide (DMF), acetone, a halogenated solvent, n-hexane, nitrobenzene, methanol, benzyl alcohol, benzaldehyde, and any combinations thereof. In some embodiments, the solvent for swelling the polyester is selected from DMSO, a halogenated solvent, and any combinations thereof. In some embodiments, the solvent for swelling the polyester is DMSO. In some embodiments, the solvent for swelling the polyester is a halogenated solvent. In some embodiments, the solvent for swelling the polyester is a chlorinated solvent. In some embodiments, the solvent for swelling the polyester is dichloromethane, dichloroethane, tetrachloroethane, chloroform, tetrachloromethane, trichloroethane, or any combinations thereof. In some embodiments, the solvent for swelling the polyester is dichloromethane. In some embodiments, the solvent for swelling the polyester is methanol.

In some embodiments, the ratio of solvent for swelling the polyester to alcoholic solvent is between about 0.1:1 and about 2:1 (w:w). In some embodiments, the ratio of solvent for swelling the polyester to alcoholic solvent is between about 1:1 and about 2:1 (w:w). In some embodiments, the ratio of solvent for swelling the polyester to alcoholic solvent is between about 0.1:1 and about 2:1 (w:w), or between about 0.2:1 and about 2:1 (w:w), or between about 0.3:1 and about 2:1 (w:w), or between about 0.4:1 and about 2:1 (w:w), or between about 0.5:1 and about 2:1 (w:w), or between about 0.6:1 and about 2:1 (w:w), or between about 0.7:1 an d about 2:1 (w:w), or between about 0.8:1 and about 2:1 (w:w), or between about 0.9:1 and about 2:1 (w:w), or between about 1:1 and about 2:1 (w:w), or between about 1:2 and about 2:1 (w:w), or between about 1:3 and about 2:1 (w:w), or between about 1:4 and about 2:1 (w:w), or between about 1:4 and about 2:1 (w:w), or between about 1:6 and about 2:1 (w:w), or between about 1:7 and about 2:1 (w:w), or between about 1:8 and about 2:1 (w:w), or between about 1:9 and about 2:1 (w:w), or between about 0.5:1 and about 1.5:1 (w:w), or between about 0.8:1 and about 1.2:1 (w:w), or between about 0.5:1 and about 1:1 (w:w), or between about 1:1 and about 1.5:1 (w:w). In some embodiments, the ratio of solvent for swelling the polyester to alcoholic solvent is between about 0.5:1 and about 1:1 (w:w).

Alkoxides

Described herein is a process for the transformation of a polyester into an ester derivative; the process comprising admixing the polyester with a mixture comprising:

-   -   (a) a solvent for swelling the polyester;     -   (b) an alcoholic solvent; and     -   (c) a sub-stoichiometric amount of an alkoxide.

In some embodiments, the process described herein comprises adding a sub-stoichiometric amount of an alkoxide. In some embodiments, the process described herein comprises adding a catalytic amount of an alkoxide.

“Sub-stoichiometric amount”, as used herein, is used to indicate that the amount of material used is less than a stoichiometric amount. The term is used herein interchangeably with “catalytic amount.” In some embodiments, a sub-stoichiometric amount is less than or equal to about 95% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 90% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 85% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 80% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 75% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 70% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 65% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 60% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 55% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 50% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 45% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 40% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 35% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 30% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 25% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 20% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 15% of a stoichiometric amount. In some embodiments, a sub-stoichiometric amount is less than or equal to about 10% of a stoichiometric amount.

“Stoichiometric amount”, as used herein, is used to indicate that the amount of material used is equivalent to the number of ester linkages present in the polyester.

In some embodiments, the alkoxide, which comprises an alkoxide anion and a cation is selected from an alkali metal alkoxide, an alkaline earth metal alkoxide, a metal alkoxide, an ammonium alkoxide, and any combinations thereof. In some embodiments, the alkoxide anion is a C₁-C₄ alkoxide anion. In some embodiments, the alkoxide anion is selected from methoxide, ethoxide, n-propoxide, n-butoxide, t-butoxide, sec-butoxide, iso-butoxide, iso-propoxide, and a combination thereof. In some embodiments, the alkoxide anion is methoxide, ethoxide, or any combinations thereof. In some embodiments, the alkoxide anion is methoxide. In some embodiments, the cation is lithium, sodium, potassium, magnesium, calcium, strontium, barium, zinc, aluminum, or ammonium. In some embodiments, the alkoxide is sodium methoxide, potassium ethoxide, or aluminium tri-n-propoxide. In some embodiments, the ammonium alkoxide is a tetraalkylammonium alkoxide. In some embodiments, the ammonium alkoxide is a tetrabutylammonium alkoxide. In some embodiments, the alkoxide is sodium methoxide, potassium ethoxide, aluminium tri-n-propoxide, or tetrabutylammonium methoxide.

In some embodiments, the alkoxide is generated in-situ by addition of an alkali metal, an alkaline earth metal, or a metal to the alcoholic solvent.

In some embodiments, the ratio of polyester to alkoxide is between about 15:1 and about 125:1 (w:w), or between about 15:1 and about 100:1 (w:w), or between about 15:1 and about 80:1 (w:w), or between about 15:1 and about 60:1 (w:w), or between about 15:1 and about 40:1 (w:w), or between about 15:1 and about 25:1 (w:w), or between about 15:1 and about 20:1 (w:w), or between about 20:1 and about 25:1 (w:w), or between about 20:1 and about 50:1 (w:w), or between about 30:1 and about 60:1 (w:w), or between about 40:1 and about 70:1 (w:w), or between about 50:1 and about 80:1 (w:w), or between about 60:1 and about 90:1 (w:w), or between about 20:1 and about 125:1 (w:w), or between about 40:1 and about 125:1 (w:w), or between about 60:1 and about 125:1 (w:w), or between about 80:1 and about 125:1 (w:w), or between about 100:1 and about 125:1 (w:w). In some embodiments, the ratio of polyester to alkoxide is between about 20:1 and about 25:1 (w:w).

Reaction Time

Described herein is a process for the transformation of a polyester into an ester derivative; the process comprising admixing the polyester with a mixture comprising:

-   -   (a) a solvent for swelling the polyester;     -   (b) an alcoholic solvent; and     -   (c) a sub-stoichiometric amount of an alkoxide.

In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed for a sufficient time. In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed until an about 70% yield of desired ester is achieved. In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed until an about 75% yield of desired ester is achieved. In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed until an about 80% yield of desired ester is achieved. In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed until an about 85% yield of desired ester is achieved. In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed until an about 90% yield of desired ester is achieved. In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed until an about 95% yield of desired ester is achieved.

In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed for between about 10 mins and 5 hrs, or between about 10 mins and 4 hrs, or between about 10 mins and 3 hrs, or between about 10 mins and 2 hrs, or between about 20 mins and 2 hrs, or between about 30 mins and 2 hrs, or between about 40 mins and 2 hrs, or between about 30 mins and 1 hr, or between about 30 mins and 1.5 hrs. In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed for about 10 mins, or about 15 mins, or about 20 mins, or about 25 mins, or about 30 mins, or about 35 mins, or about 40 mins, or about 45 mins, or about 50 mins, or about 60 mins, or about 70 mins, or about 80 mins, or about 90 mins, or about 100 mins, or about 110 mins, or about 120 mins, or about 130 mins, or about 140 mins, or about 150 mins, or about 160 mins, or about 170 min, or about 180 mins. In some embodiments, the admixing of the polyester with the solvent for swelling the polyester, the alkoxide, and the alcoholic solvent is performed for about 1 hr, or about 2 hrs, or about 3 hrs, about 4 hrs, or about 5 hrs.

Temperature

Described herein is a process for the transformation of a polyester into an ester derivative; the process comprising admixing the polyester with a mixture comprising:

-   -   (a) a solvent for swelling the polyester;     -   (b) an alcoholic solvent; and     -   (c) a sub-stoichiometric amount of an alkoxide.

In some embodiments, the process disclosed herein is conducted at ambient temperature. In some embodiments, ambient temperature is 25±5° C.

In some embodiments, the process disclosed herein is conducted without external heat. In some embodiments, the process is exothermic and the temperature of the reaction mixture rises to at least 30° C., at least 35° C., at least 40° C., at least 45° C., at least 50° C., at least 55° C., or at least 60° C. In some embodiments, no external heat sources are used to increase the temperature of the reaction mixture.

In some embodiments, the process disclosed herein is conducted with external heat. In some embodiments, the process disclosed herein is conducted with external heat at between about 25° C. and about 80° C., or between about 25° C. and about 60° C., or between about 40° C. and about 60° C., or between about 40° C. and about 50° C., or between about 30° C. and about 50° C. In some embodiments, the process disclosed herein is conducted at about 26° C., about 27° C., about 28° C., about 29° C., about 30° C., about 31° C., about 32° C., about 33° C., about 34° C., about 35° C., about 36° C., about 37° C., about 38° C., about 39° C., about 40° C., about 41° C., about 42° C., about 43° C., about 44° C., about 45° C., about 46° C., about 47° C., about 48° C., about 49° C., about 50° C., about 51° C., about 52° C., about 53° C., about 54° C., about 55° C., about 56° C., about 57° C., about 58° C., about 59° C., about 60° C., about 65° C., about 70° C., about 75° C., or about 80° C.

Pressure

In some embodiments, the process disclosed herein is conducted at atmospheric pressure. In some embodiments, the process disclosed herein is conducted at elevated pressures. In some embodiments, the process disclosed herein is conducted at a pressure between about atmospheric pressure and about 220 psi, or between about atmospheric pressure and about 200 psi, or between about atmospheric pressure and about 150 psi, or between about atmospheric pressure and about 100 psi, or between about atmospheric pressure and about 50 psi, or between about 20 and about 150 psi, or between about 50 and about 100 psi. In some embodiments, the process disclosed herein is conducted at about 14 psi, about 15 psi, about 16 psi, about 17 psi, about 18 psi, about 19 psi, about 20 psi, about 30 psi, about 40 psi, about 50 psi, about 60 psi, about 70 psi, about 80 psi, about 90 psi, about 100 psi, about 110 psi, about 120 psi, about 130 psi, about 140 psi, about 150 psi, about 160 psi, about 170 psi, about 180 psi, about 190 psi, about 200 psi, about 210 psi, or about 220 psi.

Agitation

Described herein is a process for the transformation of a polyester into an ester derivative; the process comprising admixing the polyester with a mixture comprising:

-   -   (a) a solvent for swelling the polyester;     -   (b) an alcoholic solvent; and     -   (c) a sub-stoichiometric amount of an alkoxide.

In some embodiments, the process disclosed herein is conducted without agitation. In some embodiments, the process disclosed herein is conducted with increased agitation. In some embodiments, a stirred batch reactor is used to provide agitation. In some embodiments, a continuous reactor is used to provide agitation.

Certain Terminology

The section headings used herein are for organizational purposes only and are not to be construed as limiting the subject matter described.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as is commonly understood to which the claimed subject matter belongs. In the event that there are a plurality of definitions for terms herein, those in this section prevail.

It is to be understood that the general description and the detailed description are exemplary and explanatory only and are not restrictive of any subject matter claimed. In this application, the use of the singular includes the plural unless specifically stated otherwise. It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise. In this application, the use of “or” means “and/or” unless stated otherwise. Furthermore, use of the term “including” as well as other forms, such as “include”, “includes,” and “included,” is not limiting.

Unless the context requires otherwise, throughout the specification and claims which follow, the word “comprise” and variations thereof, such as, “comprises” and “comprising” are to be construed in an open, inclusive sense, that is, as “including, but not limited to.” Further, headings provided herein are for convenience only and do not interpret the scope or meaning of the claimed invention.

As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. It should also be noted that the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.

As used herein, the term “about” or “approximately” means within 10%, preferably within 10%, and more preferably within 5% of a given value or range.

As used herein, ambient temperature is a colloquial expression for the typical or preferred indoor (climate-controlled) temperature to which people are generally accustomed. It represents the small range of temperatures at which the air feels neither hot nor cold, approximately 21° C. In some embodiments, ambient temperature is 25±5° C. In some embodiments, ambient temperature is 18° C. In some embodiments, ambient temperature is 19° C. In some embodiments, ambient temperature is 20° C. In some embodiments, ambient temperature is 21° C. In some embodiments, ambient temperature is 22° C. In some embodiments, ambient temperature is 23° C. In some embodiments, ambient temperature is 24° C. In some embodiments, ambient temperature is 25° C. In some embodiments, ambient temperature is 26° C. In some embodiments, ambient temperature is 27° C. In some embodiments, ambient temperature is 28° C. In some embodiments, ambient temperature is 29° C. In some embodiments, ambient temperature is 30° C.

As used in this specification and the appended claims, depolymerization, refer to a way of breaking down a polymer to its starting material. It is essentially the opposite of polymerization. In some embodiments, the depolymerization is achieved by glycolysis, methanolysis or hydrolysis, categorized by the depolymerization reactant used, such as glycol, methanol or water, respectively.

As used herein, the term “mol” when referring to PET is the molar amount and is calculated using the molecular weight of the “PET” unit which is 192.17 g/mol.

Definition of standard chemistry terms may be found in reference works, including but not limited to, Carey and Sundberg “Advanced Organic Chemistry 4^(th) Ed.” Vols. A (2000) and B (2001), Plenum Press, New York.

The terms below, as used herein, have the following meanings, unless indicated otherwise:

-   -   “Alkyl” refers to a straight or branched hydrocarbon chain         radical which is attached to the rest of the molecule by a         single bond. A linear alkyl comprising up to 4 carbon atoms is         referred to as a linear C₁-C₄ alkyl, likewise, for example, a         linear alkyl comprising up to 3 carbon atoms is a linear C₁-C₃         alkyl. Linear alkyl groups include linear C₁-C₄ alkyl, linear         C₁-C₃ alkyl, linear C₁-C₂ alkyl, linear C₂-C₃ alkyl and linear         C₂-C₄ alkyl. Representative alkyl groups include, methyl, ethyl,         propyl, and butyl. A branched alkyl comprising between 3 and 4         carbon atoms is referred to as a branched C₃-C₄ alkyl.         Representative branched alkyl groups include, but are not         limited to t-butyl, sec-butyl, isobutyl, and isopropyl. Unless         stated otherwise specifically in the specification, an alkyl is         optionally substituted with oxo, halogen, —CN, —CF₃, —OH, —OMe,         —NH₂, or —NO₂. In some embodiments, an alkyl is optionally         substituted with oxo, halogen, —CN, —CF₃, —OH, or —OMe. In some         embodiments, the alkyl is optionally substituted with halogen.     -   “Halo” or “halogen” refers to bromo, chloro, fluoro or iodo. In         some embodiments, halogen is fluoro or chloro. In some         embodiments, halogen is fluoro.     -   “Haloalkyl” refers to an alkyl radical, as defined above, that         is substituted by one or more halo atoms, as defined above,         e.g., trifluoromethyl, difluoromethyl, fluoromethyl,         trichloromethyl, 2,2,2-trifluoroethyl, 1,2-difluoroethyl,         3-bromo-2-fluoropropyl, 1,2-dibromoethyl, and the like.     -   “Hydroxyalkyl” refers to an alkyl radical, as defined above,         that is substituted by one or more —OH groups, e.g.,         hydroxymethyl, hydroxyethyl, hydroxypropyl, propanediol, and the         like.     -   “Cycloalkyl” refers to a stable, partially or fully saturated,         monocyclic or polycyclic carbocyclic ring, which may include         fused or bridged ring systems. Representative cycloalkyls         include, but are not limited to, cycloalkyls having from three         to fifteen carbon atoms (C₃-C₁₅ cycloalkyl), from three to ten         carbon atoms (C₃-C₁₀ cycloalkyl), from three to eight carbon         atoms (C₃-C₈ cycloalkyl), from three to six carbon atoms (C₃-C₆         cycloalkyl), from three to five carbon atoms (C₃-C₅ cycloalkyl),         or three to four carbon atoms (C₃-C₄ cycloalkyl). In some         embodiments, the cycloalkyl is a 3- to 6-membered cycloalkyl. In         some embodiments, the cycloalkyl is a 5- to 6-membered         cycloalkyl. Monocyclic cycloalkyls include, for example,         cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl,         and cyclooctyl. Polycyclic cycloalkyls or carbocycles include,         for example, adamantyl, norbornyl, decalinyl,         bicyclo[3.3.0]octane, bicyclo[4.3.0]nonane, cis-decalin,         trans-decalin, bicyclo[2.1.1]hexane, bicyclo[2.2.1]heptane,         bicyclo[2.2.2]octane, bicyclo[3.2.2]nonane, and         bicyclo[3.3.2]decane, and 7,7-dimethyl-bicyclo[2.2.1]heptanyl.         Partially saturated cycloalkyls include, for example         cyclopentenyl, cyclohexenyl, cycloheptenyl, and cyclooctenyl.         Unless stated otherwise specifically in the specification, a         cycloalkyl is optionally substituted with oxo, halogen, methyl,         ethyl, —CN, —CF₃, —OH, —OMe, —NH₂, or —NO₂. In some embodiments,         a cycloalkyl is optionally substituted with oxo, halogen,         methyl, ethyl, —CN, —CF₃, —OH, or —OMe. In some embodiments, the         cycloalkyl is optionally substituted with halogen.     -   “Aryl” refers to a radical derived from a hydrocarbon ring         system comprising hydrogen, 6 to 30 carbon atoms and at least         one aromatic ring. The aryl radical may be a monocyclic,         bicyclic, tricyclic or tetracyclic ring system, which may         include fused or bridged ring systems. In some embodiments, the         aryl is a 6- to 10-membered aryl. In some embodiments, the aryl         is a 6-membered aryl. Aryl radicals include, but are not limited         to, aryl radicals derived from the hydrocarbon ring systems of         anthrylene, naphthylene, phenanthrylene, anthracene, azulene,         benzene, chrysene, fluoranthene, fluorene, as-indacene,         s-indacene, indane, indene, naphthalene, phenalene,         phenanthrene, pleiadene, pyrene, and triphenylene. In some         embodiments, the aryl is phenyl. Unless stated otherwise         specifically in the specification, an aryl may be optionally         substituted, for example, with halogen, amino, nitrile, nitro,         hydroxyl, alkyl, alkenyl, alkynyl, haloalkyl, alkoxy, aryl,         cycloalkyl, heterocycloalkyl, heteroaryl, and the like. In some         embodiments, an aryl is optionally substituted with halogen,         methyl, ethyl, —CN, —CF₃, —OH, —OMe, —NH₂, or —NO₂. In some         embodiments, an aryl is optionally substituted with halogen,         methyl, ethyl, —CN, —CF₃, —OH, or —OMe. In some embodiments, the         aryl is optionally substituted with halogen.

EXAMPLES

The following examples are intended to illustrate but not limit the disclosed embodiments.

Example 1

Polyethylene terephthalate (1000 g) was introduced in a reactor. Dichloromethane (500 g) was added and the mixture was stirred at room temperature and at atmospheric pressure for about 40 mins. Sodium methoxide and methanol were then added to the reaction mixture was stirred and heated for 120 mins (see table below for amounts, time, and temperature details).

The reaction mixture was then filtered and the filter cake was washed with methanol. The filter cake was then melted and filtered at 140° C. to remove any unreacted materials. The filtered dimethyl terephthalate was then distilled under vacuum at 200° C. The liquid recovered from the filtration was distilled to recover the solvents and the mono ethylene glycol.

Weight of Weight of sodium Reaction Reaction methanol methoxide time temperature Yield (g) (g) (min) (° C.) (%) Example 667 32 120 55 90 1A Example 600 54 120 50 90 1B Example 580 50 120 60 90 1C

Example 2

Polyethylene terephthalate (1000 g) was introduced in a reactor. DMSO (500 g) was added and the mixture was stirred at room temperature and at atmospheric pressure for about 40 mins. Sodium methoxide (45 g) and methanol (550 g) were then added to the reaction mixture was stirred and heated at 55° C. for 120 mins.

The reaction mixture was then filtered and the filter cake was washed with methanol. The filter cake was then melted and filtered at 140° C. to remove any unreacted materials. The filtered dimethyl terephthalate was then distilled under vacuum at 200° C. The liquid recovered from the filtration was distilled to recover the solvents and the mono ethylene glycol.

Dimethyl terephthalate was obtained in 89% yield.

Example 3: Mono Sodium Glycoxide Formation Dissolution Step:

Mono ethylene glycol (MEG, 2447.7 g) was added to a 6 L glass reactor and heated to 90° C. while stirring at 230 RPM. Sodium hydroxide (NaOH, 1770.6 g, as micro granules) were slowly added (very exothermic). MEG/NaOH (mol/mol): 1 to 1.2:1. The temperature of the mixture after addition of sodium hydroxide was monitored and recorded). The mixture was stirred (280 RPM) while maintaining the temperature at 150° C. for about 10 minutes (to make sure that all the sodium hydroxide dissolves). The liquid obtained was spread on Pyrex® plates and placed in a vacuum oven (at 130° C. and −30 inches of Hg pressure) for 60 minutes. The vacuum oven chamber was purged with nitrogen and placed back under vacuum. The plates were dried for about 12 hours. Once the catalyst is dry it was removed from the vacuum oven, grinded, and placed again in the vacuum oven (at 130° C. and −30 inches of Hg pressure). The vacuum oven chamber was purged with nitrogen and placed back under vacuum. The catalyst was dried for about 12 hours. Once the catalyst is dried it was removed from the vacuum oven and added to a Pyrex® bottle. Methanol was added (ratio catalyst/MeOH (mol/mol): 0.18:1) and stirred for 30 minutes. The suspension was kept in a flammable cabinet for up to one week.

Example 4: Depolymerization of Polyethylene Terephthalate Swelling and Rinse:

The polyethylene terephthalate feedstock (10 Kg) was added to a jacketed with a scraped double motion agitation (hermetically closed) reactor. The reactor was purged with nitrogen for 3 minutes. Methanol (6 Kg) was added and the resulting mixture was heated at about 60° C. and stirred at 60 rpm for about 60 minutes. The pressure and temperature were recorded. A portion of the liquid (3.5 Kg) was drained.

Reaction:

The reactor's central agitation was started (155 RPM). The scraper was started (70 RPM). The heat was increased to about 85° C. The glycoxide suspension (973.5 g, 31.5 weight % glycoxide) was added and the mixture was heated and stirred for 5 minutes. The pressure and temperature were recorded. Additional methanol (3.83 Kg) was added and the resulting mixture was reacted for about 360 minutes (after reaching temperature). The mixture was then cooled to 25° C.

Filtration:

The solid was filtered and washed with methanol (4.8 Kg). The filter cake (dimethyl terephthalate) was weighted.

Distillation:

DMT recovery: The cake containing the DMT and the unreacted material was melted at 150° C. The mixture was then evaporated or distilled in a thin film or a distillation column or any evaporation or distillation system at 160° C. under 2 torr of vacuum or 180° C. under 50 torr of vacuum. The DMT was recovered as a solid or as a liquid if the receiving system is heated at 150° C.

MEG recovery: The mother liquor containing the MEG and methanol was passed through an evaporation or distillation system such as a thin film, a distillation column, an evaporator, etc, to remove around 70% of the methanol (at 30° C. under full vacuum). The recovered slurry was then chilled at 3 to −6° C. and filtered. A liquid was recovered and the residual 30% of methanol was removed by evaporation or distillation. The MEG left was then distilled or evaporated at 100° C. under full vacuum.

DMT yields using various amounts of catalysts and different catalysts are shown in the table below. For all examples:

-   -   The molar PET amount (calculated using the “PET” unit molecular         weight of 192.17 g/mol) was 52 mol;     -   The Molar amount of methanol was 218 mol;     -   The temperature was 70° C.;     -   The Reaction time was 480 mins.

Catalyst Pressure DMT Catalyst Amount (mol) (psi)¹ Yield (%)² Mono sodium 9.2 9 99 glycoxide Sodium 9.2 13 99 methoxide Mono sodium 5.5 8 99 glycoxide Sodium 5.5 10 98 methoxide Mono sodium 3.7 8 99 glycoxide Sodium 3.7 11 96 methoxide ¹pressure generated in hermetically closed reactor. ²before DMT distillation.

MEG yields using different catalysts are shown in the table below:

Amount of MEG Amount of MEG Yield Yield of Amount of in the mother MEG (based on the Catalyst conversion MEG liquor after recovered by amount found Amount Pressure to MEG generated filtration one distillation in the mother Catalyst (mol) (psi) (%) (mol) (mol) (mol) liquor) Sodium 5.2 8 99 51.5 46.7 38.7 83% glycoxide Sodium 5.2 10 98 51.0 46.0 32.1 70% methoxide 

What is claimed is:
 1. A process for the depolymerization of a polyester to form a terephthalate, the process comprising: (a) admixing the polyester with a first portion of an alcohol to yield a first mixture, wherein the admixing is performed at a temperature from about 50° C. to about 100° C.; (b) adding a sub-stoichiometric amount of a metal methoxide and a second portion of the alcohol to the first mixture to yield a second mixture, wherein the sub-stoichiometric amount of the metal methoxide is from about 30:1 to about 100:1 (w/w) of the polyester to the metal methoxide; and (c) admixing the second mixture, wherein the admixing is performed at a temperature from about 70° C. to about 100° C., thereby forming the terephthalate with at least about 70% yield within about 2 hours.
 2. The process of claim 1, wherein a sub-stoichiometric amount of the metal methoxide is added to the first mixture.
 3. The process of claim 2, wherein the sub-stoichiometric amount of the metal methoxide is from about 30:1 to about 100:1 (w/w) of the polyester to the metal methoxide.
 4. The process of claim 1, wherein the metal methoxide comprises an alkali metal methoxide.
 5. The process of claim 4, wherein the alkali metal methoxide comprises sodium methoxide.
 6. The process of claim 1, wherein the metal methoxide comprises an alkaline-earth metal methoxide.
 7. The process of claim 6, wherein the alkaline-earth metal methoxide comprises calcium methoxide.
 8. The process of claim 1, further comprising, prior to (a), generating the metal alkoxide in-situ by addition of a metal of the metal alkoxide to the first portion of the alcohol.
 9. The process of claim 1, wherein the admixing the polyester with the first portion of the alcohol is performed at a temperature from about 70° C. to about 100° C.
 10. The process of claim 1, wherein the admixing the second mixture is performed at a pressure from about atmospheric pressure to about 220 psi.
 11. The process of claim 10, wherein the admixing the second mixture is performed at a pressure from about atmospheric pressure to about 150 psi.
 12. The process of claim 1, wherein the alcohol comprises methanol.
 13. The process of claim 1, wherein the alcohol comprises ethanol.
 14. The process of claim 1, wherein the terephthalate comprises dimethyl terephthalate.
 15. The process of claim 1, wherein the polyester comprises polyethylene terephthalate.
 16. The process of claim 1, wherein the polyester comprises polybutylene terephthalate.
 17. The process of claim 1, wherein the admixing the second mixture is performed at a temperature from about 70° C. to about 90° C.
 18. The process of claim 1, wherein the admixing the second mixture is performed at a temperature from about 80° C. to about 100° C.
 19. The process of claim 18, wherein the admixing the second mixture is performed at a temperature of about 85° C.
 20. The process of claim 18, wherein the admixing the second mixture is performed at a temperature of about 90° C. 